You should be able to find an engineer or timber grader who can do this work for you. There are guidelines similar to the knot size and grading rules for the various defects found in reclaimed. I've worked on many projects which required graded material and a sealed timber list (reclaimed typically doesn't come with a grade stamp) - including several projects in earthquake country - shallow trusses, high snow load - but narrow pieces of beautiful reclaimed fir.
How are you procuring timber?
In my years working with New Energy Works and Pioneer Millworks we did (and still do) this all the time. Often we would design the frame for optimal sizing, then seek out what reclaimed materials are available - and speciify what grade they need to meet - often redesigning a bit along the way (ie - if we found a stash of 3x10s that could be used as common rafters instead of the 4x8's specified).
A competent reclaimed supplier / mill should be able to visually grade to a #1 or BTR in Reclaimed Fir, Heart Pine, and probably mixed softwoods. Note - I'm assuming re-sawn industrial salvage reclaimed - but it can be done with 'as found' industrial salvage as well.
If you are talking about agricultural salvage - that is a very different problem - sawn or not - as mortise location and repetition from barn timbers (typically hewn) and damage from weather, rot, and insect make it far more challenging.
Its a chicken / egg problem no matter how you look at it - we're just lucky that currently we can all pick whatever timber we want 'off the shelf' of the fresh sawn forest. There are creative ways to work with what the forest (industrial buildings or local mountainsides) gives us... and in a world of declining resources - at some point we probably won't be able to order up whatever we want, whenever we want...
-Mike
Last edited by bmike; 02/14/09 01:00 AM.
